The present invention relates generally to medicine, and more particularly, to anesthesia, emergency medicine, intensive therapy, and veterinary medicine.
The laryngeal mask airway (LMA) disclosed in U.S. Pat. No. 4,509,514 is an artificial airway device designed to facilitate ventilation of an unconscious patient, and is used in over 80 countries. An unconscious patient, undergoing ventilation whether spontaneous or controlled via an LMA, may regurgitate or vomit gastric contents, as may happen if the stomach is not empty before such ventilation. Leakage of such gastric contents into the lungs should be prevented because it may be fatal. U.S. Pat. No. 5,241,956 describes modified laryngeal masks including a tube for entry into the oesophagus (i.e., gullet) to drain liquid gastric contents therefrom. A laryngeal mask including a drainage tube for extraction of gastric drainage is also disclosed in U.S. Pat. No. 5,632,271.
Providing a laryngeal mask which retains the ease of use of the original but also has a tube for drainage of gastric contents, may be difficult. Additionally, installation in a patient of a laryngeal mask having a large-bore gastric drainage tube (e.g., as described in U.S. Pat. No. 5,241,956) may be more difficult as compared to a standard LMA device. Also, while a laryngeal mask having a smaller-bore gastric drainage tube is typically easier to install in a patient, the flow capacity of such a drainage tube for gastric contents (resulting, for example, from vomiting) may be more limited. Moreover, a laryngeal mask having a smaller-bore gastric drainage tube may not be able to accommodate a large stomach tube (e.g., of greater than 6 mm OD).
The disclosures of all of the above referenced patents are hereby incorporated by reference.